Bionic Hand: Prosthesis with moving fingers

In the summer 2007 “Touch Bionics” presented the “i-Limb” a hand prosthesis, where each of the five fingers is moved with their own separate motor.

The Scottish company Touch Bionics announced the introduction of the first bionic hand. The artificial hand called “i-Limb” is according to its own data, the first available prosthesis with five individually moving fingers that behave just like a real human hand. “The technology on which the i-Limb was built is the result of many years of research and development”, explains the developer David Gow.

Myoelectric Signals

The i-LIMB Hand is controlled by a unique, highly intuitive control system that uses a traditional two-input myoelectric (muscle signal) to open and close the hand’s life-like fingers. Myoelectric controls utilize the electrical signal generated by the muscles in the remaining portion of the patient’s limb. This signal is picked up by electrodes that sit on the surface of the skin.

i-LIMB (Picture: Touch Bionics)

Fingers can be moved independently of each other

The i-Limb Hand has individually powered digits, which allows each finger to move independently. Further more the prosthesis is pressure sensitive and allows the user to take easily deformable objects like a Styrofoam cup in the hand, without crushing it. A sensor determines the amount of pressure applied and stops the motors when it is enough to hold the given object.

Unit price c. €12,500

For users of traditional myoelectric hands, the transition to the new system presents no problems; according to the producer, the functions of the i-Limb can be learned within a few minutes. A press release by Touch Bionics, reported that, in large clinics in the USA, veterans of the Iraq war have already been fitted out with the i-Limb. The price of the i-Limb prosthetic is currently around €12,500.